/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.datasource.embedded;

import java.sql.Driver;

import org.springframework.lang.Nullable;
import org.springframework.util.ClassUtils;

/**
 * {@link EmbeddedDatabaseConfigurer} for an H2 embedded database instance.
 * <p>Call {@link #getInstance()} to get the singleton instance of this class.
 *
 * @author Oliver Gierke
 * @author Juergen Hoeller
 * @author Sam Brannen
 * @since 3.0
 */
final class H2EmbeddedDatabaseConfigurer extends AbstractEmbeddedDatabaseConfigurer {

    @Nullable
    private static H2EmbeddedDatabaseConfigurer instance;

    private final Class<? extends Driver> driverClass;


    /**
     * Get the singleton {@code H2EmbeddedDatabaseConfigurer} instance.
     *
     * @return the configurer
     * @throws ClassNotFoundException if H2 is not on the classpath
     */
    @SuppressWarnings("unchecked")
    public static synchronized H2EmbeddedDatabaseConfigurer getInstance() throws ClassNotFoundException {
        if (instance == null) {
            instance = new H2EmbeddedDatabaseConfigurer((Class<? extends Driver>)
                    ClassUtils.forName("org.h2.Driver", H2EmbeddedDatabaseConfigurer.class.getClassLoader()));
        }
        return instance;
    }


    private H2EmbeddedDatabaseConfigurer(Class<? extends Driver> driverClass) {
        this.driverClass = driverClass;
    }

    @Override
    public void configureConnectionProperties(ConnectionProperties properties, String databaseName) {
        properties.setDriverClass(this.driverClass);
        properties.setUrl(String.format("jdbc:h2:mem:%s;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false", databaseName));
        properties.setUsername("sa");
        properties.setPassword("");
    }

}
